Charles e



(No Modgal.)

G. E. SORIBNER.

APPARATUS FOR TELEPHONE SWITCHBOARDS. No. 597,785 Patented Jan. 25, 1898.

wfor 2 1 635 UNiTED STATES PATENT rrrcn.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TC) THE WESTERN ELECTRIC COMPANY, OF SAME PLACE.

APPARATUS FOR TELEPHONE-=SVVITCHBOARDS.

SPECIFICATION formingpart of Letters Patent No. 597,785, dated January 25, 1898.

Application filed April 16,1895.

To ctZZ whom it may concern.-

Be it known that I, CHARLES E. SCRIBNER, a citizen of the United States, residing at Ohicago, in the county of Cook and State of Illinois, have inventedacertainnew and useful Improvement in Apparatus for Telephone- Switchboards, (Case No. 380,) of which the following is a full, clear, concise, and exact description,reference being had to the acconipa- 1o nying drawing, forming a part of this specification.

My invention relates to signaling apparatus for use between substations and the central station of a telephone-exchange, particularly r 5 to the type of signaling mechanism in which a relay in the line-circuit controls a subsidiary or auxiliary signal in a local circuit.

The object of my present invention is to construct a system of this type adapted for use with mornentarily-actuated generators of signaling-current located at substations,making the display of the subsidiary signals attendant upon the operation of the generator of signaling-current at the substation, but

2 5 permitting its subsequent continued display independent of current in the line-circuit.

A further object is to return the displayed subsidiary signal to its normal inert condition when connection is established with the 0 line in response to a call, leaving the subsidiary signals free for further operation after the withdrawal of the connections.

The primary object of my invention is attained by the combination, with a telephone- 3 5 line provided with a suitable source of signailing-current in its circuit, such as a momentarily-actuated generator at the substation, and terminating in a telephoneswitchboard, of a relay and a local circuit including 0 a subsidiary signal and a source of current controlled by the armature of the relay and a secondary or auxiliary magnet-coil upon the relay included in the local circuit. By this device the establishment of current in the line-circuit magnetizes the relay, which closes the local circuit and excites the subsidiary signal, at the same time energizing the auxiliary magnet-coil on the relay and thus retaining its armature in position to maintain 5c the excitement of the subsidiary signal witherialllb. 545,854. (No model.)

out further dependence upon the current in the line-circuit.

The second-mentioned object of the invention is attained by an arrangement of circuits and switch-contacts for short-c-ircuiting or otherwise deenergizing the auxiliary magnet-helix of the relay when connection is es tablished with the line, whereby the relay is permitted to resume its normal condition and the subsidiary signal to become inert. Conductors from opposite terminals of the auxiliary magnet-helix are led to registering contact-pieces in the spring-jacks oi the line and in the connecting-plugs which are adapted for use with them. Thus when a plug is inserted 6 5 into a spring-jack the auxiliary inagncthelix is short -circuited. I have found small incandescent lamps to be suitable subsidiary signals for use in such local circuits. The auxiliary magnet helinthe contact-points of the relay, the subsidiary lamp-signal, a re sistance-coil, and a source of current are in cluded in the order of naming in the local circuit. A connection is taken from this circuit at a point between the lamp and the re- 7 5 sistance-coil to a contact-piece in a springjack, or in each spring-jack connected with the same line if the switchboard be of the multiple type, and another conductor is led from the contact-piece in each connecting 8o plug to a point between the battery and the auxiliary magnethelimthese latter points being common to the different pairs of cords and local circuits. Thus when in establishing connection with a line a connecting-plug is inserted into a spring-jack of the line a shunt or short circuit is formed about the auxiliary magnet-helix, the contact-points of the relay, and the lamp, whereby the relay is demagnetized and the lamp is extinguished. 0 When the connecting-plug is withdrawn from the spring-jack, there being then no current either in the line-circuit or in the local circuit, the relay remains in its inert condition in readiness to respond to a subsequent signal- 5 ing-current in the line.

While the individual or line signal of any line is rendered inoperative during the use of theline, it is of course necessary that some means he provided for receiving or indicating 10a responding lines.

a signal, such as a signal for disconnection or removal of the connection between two cor For this purpose in my system I have arranged a device for responding to a clearing-out signal, which is temporarily associated with two connected lines, consisting of substantially the same mechanism with the same general arrangement as employed in the line-circuit. The main or line magnet of a relayis connected in a bridge between the different conductors of the plugcircuit uniting the two connecting-plugs, and the switch-contacts of the relay control a local circuit, including a source of current, a subsidiary lamp-signal, and the auxiliary magnet of the relay. \Vhen the line-magnet of the relay is excited by a signaling-current in the line subsequent to the establishment of connection with the line and, as before described, closes the local circuit, it illuminates the subsidiary lamp-signal and creates at the same time an exciting-current through the relay which is independent of the current in the line. Upon the return of the connecting-plugs to their normal or idle position the local circuit is interrupted bya suitable switch actuated in the replacement of one of the plugs in its resting-socket.

I have illustrated my invention in the accompanying drawing, which is a diagram representing two substations connected by line circuits with relays and spring-jacks in a telephoneswitchboard, the relays being associ ated with local circuits and subsidiary signals, as before described. A single pair of connecting-plugs is shown, the plugs being equipped 'with the clearing-out device men tioned.

The mechanism provided at the subscribers station comprises the usual telephonereceiver a and transmitter a, signal-bell a and generator of signaling-current (L together with a switch a arranged to support the telephone and constructed to close the circuit alternately through the telephone instruments and the signaling appliances. The line-circuit, consisting of direct and return conductors l and 2, connects this apparatus with spring-jacks b and b in a multiple telephone-switchboard of two sections and c, and includes the line-helix d of a relay 6, located at the central station. The armature cl and contact-anvil d of this relay control the continuity of a local circuit 3, which extends serially through an auxiliary Inagnet= helix d on relay e, a signal-lamp f, a resistance-coil g, and a battery 71. The signal-lamp f is located in any convenient position in the switchboard where it may be under the supervision of the attendant, preferably near the spring-jack b of the line on section 0 of the switchboard. .A suitable lamp may have a resistance of ten ohms. The resistance of magnet-helix d should be comparatively low in order to avoid waste of energy in the local circuit, five ohms being suflicient. The resistance of coil 9 may also be ten ohms. The

electromotive force of battery h should or course be sufticient to cause theillumination of signal-lamp f when the relay-contacts are closed.

The spring-jack which constitutes the terminal of the line in each section of the switchboard is of well-known construction. It coniprises two springs 1' and t",which are connected with line conductors 1 and 2, respectively,and a contact ring or thimble The thimbles t of the different spring-jacks are united by a conductor 4, which is connected with the local circuit 3 at a point intermediate of the lamp and the resistance-coil.

The connecting-plug employed is constructed with three contact-pieces 7a, 7a, and If, which are adapted to register with the different contact-pieces 2", i, and 2' of a springjack, into which a plug maybe inserted. The contact-pieces 7c and the contact-pieces 7c of two plugs l and Z are united by two conductors 5 and 6, which constitute the plugcircuit. These conductors include the switch-contacts of a calling-key m, which is adapted to disconnect the plug Z from plug land to loop into circuit with the former a source of calling-current n for the purpose of signaling a subscriber. Conductors 5 and 6 are connected with the switch-contacts or a listening-key also, which acts when depressed to bridge the operators telephone set 19 across the plug-circuit. A conductor 7 is led from the central point of the resistance in the magnet-helix of the telephone-receiver p to a point on circuit 3 intermediate of the battery hand the resistance-coils g to provide means for testing, as will be hereinafter described. v

The line-coil cl of a clearing-out relay q is permanently connected in a bridge 8 between conductors' 5 and 6. The switch-contacts d d of this relay control the continuity of another local circuit 9, which likewise includes an auxiliary magnet d on the relay, a signal-lamp r, and a battery. The same batteryh is employed, the local circuit 9 being placed in parallel with the local circuit 3 about the battery. The continuity of this circuit 9 is further controlled by a plug-seat switch 8 in the resting-socket of plug 1, the plug-seat switch being arranged to close the circuit when the plug is Withdrawn from its socket. The contact-pieces 70 of the two plugs are grounded through conductors l0 and'll, respectively. v

In the normal condition of the apparatus the telephones at the different substations rest upon their switch-hooks and no currents exist in the linecircuits. The armatures oi the relays are retracted from their contactpoints. The local circuits are open and the different linesignals are inert or unilluminated. The plugs-l of the different pairs of cords provided for. each operator rest in their sockets, whereby the different circuits 9 are interrupted,

To illustrate the operation of the system,

assume that the subscriber at station A desires to have his line connected with station B. The subscriber at the former station operates his generator of signaling-current in .the usual way, thus creating in the line-circuit l 2 a current which traverses the linemagnet d of relay e. The relay is excited and closes the local circuit 3. The current of battery it of this local circuit illuminates the signal-lamp f, associated with the spring- ;jack of that line on switchboard c, and at the same time further excites the relay 6, so that after the cessation of the signaling-current in the line-circuit the relay still holds its armature and maintains the illumination of lamp f. The attendant at section 0 of the switch board, observing the signal, raises plug Z from its socket and inserts it into the springjack (2'. The raising of the plug from its socket permits the plug-seat switch 8 to close one break in the local circuit 9, thus leaving this circuit with its clearing-out signal-lamp controlled only by the relay q. The insertion of plugZ into the spring-jack extends the line conductors 1 2 to the conductors 5 6 of the plug-circuit through the medium of the registering contacts of the spring-jack and the plug. At the same time a ground connection is completed from ring 6 through contact-piece k and conductor 10, terminatin g therein, which constitutes a shunt or short circuit about the lamp f, the contactpoints of relay 6, and the magnet 61 of the relay. The lamp f is thus extinguished, and the magnetizing-helix (Z becomes inert and permits the armature of the relay to fall away from its contact.

The operator connects her telephone set with the plug-circuit by means of key 0 in the usual manner, and having thus established communication with the subscriber at station A learns his order. She tests the line to station B in the usual waythat is, by applying the tip of plug Z to the thimble or ring i of spring-jack Z1 If the line be not in use, no difference of potential exists between the tip oi the plug and the ring of the springjack, since these constitute the terminals of open circuits whose other terminals are connected with the same pole of battery 72-, the rings being the open terminals of the circuit at 3 and the tip of the plug being the terminal of a circuit through conductor 6 to the listening-key and thence through the operators telephone-receiverp and conductor 7 to the battery it. If the line were in use, the ring 1' of spring-jack b would be grounded through conductor 10 or 11 of the plug-circuit, by

means of which the connection with it was established, and battery h would find a circuit through the tip of the plug to earth at each application of the plug to the test-ring '6 Finding the line free for the desired connection, she inserts plug Z into the springjaok b and operates the key on to ring the bell at substation B, as usual. The insertion of the plug into the spring-jackcreates a short circuit about the lamp-signal f and the magnet (i of relay 6 by means of the conductor 11, connected with the plug in a manner similar to that established about the signal and relay magnet of the other line. Hence although a portion of the signaling-current traverses the linemagnet of relay 6 the line signal-lamp f is not illuminated. It will be understood that the signal-lamp f may be upon any section of a multiple switchboard, and that its illumination by a signaling-current sent to operate the substation-bell would constitute a false signal, which would mislead the operator having supervision of the signal-lam p.

hen the subscribers have terminated their conversation, either subscriber may transmit a signal for disconnection by turning his generator 0. of signalingcurrent. The current thus created in the line finds circuit to the plug-circuit 5 6 and thence through the line-magnet (Z of the clearing-out relay g. This relay becomes excited and closes the local circuit 9, illuminating the clearing-out signal-lamp r and thus indicating the signal to the attendant. The continued excitement of the relay after the cessation of the signaling-current is attained, as before, by the magnetism of helix 01 In response to the signal the operator removes the plugs Z Z from the spring-jacks into which they are inserted and returns them to their resting-sockets. The plug-seat switch interrupts the local circuit 9, the relay-magnet becomes inert, and the mechanism of the clearing-out device is returned to its normal condition.

It will be noted that the relay 6 is not excited at thefmoment of withdrawal of plugZ from spring-jack b", so that it remains in its normal position in readiness to indicate a subsequent line-signal.

I do not desire to limit myself to any particular mode of producing current in the linecircuit for the purpose of exciting the relay or to the location of the source of current at the substation, since my invention maybe easily adapted to different systems involving various sources of current-supply for signaling.

In accordance with the foregoing specification I claim as new and desire to secure by Letters Patent- 1. The combination with a telephone-line, of means for producing a signaling-current in the line, and a relay in the circuit responding to such current, a local circuit including a subsidiary line-signal controlled by the relay, an auxiliary helix on the relay in the 10- cal circuit, means for establishing connection with the line, and switch-contacts actuated in the establishment of such connection adapted to interrupt the current through the said auxiliary helix, substantially as described.

2. The combination with a telephone-line and means for producing signaling-current therein, of a relay in the line-circuit, a local circuit including a subsidiary line-signal and a source of current, controlled by the relay, an auxiliary magnet-helix on the relay, in the local circuit, spring-jacks and connecting plugs for making connection with the line, and a normally open short circuit about the auxiliary helix and the subsidiary line-signal, and cooperating contacts in the plug and spring-jack adapted to close the short circuit, substantially as described.

3. The combination With a telephone-line and means for producing signaling-current therein, of a relay in the line-circuit, a local. circuit including a subsidiary line-signal controlled by the relay, an auxiliary magnethelix on the relay, included in the local circuit, springjacks connected with the line and a connecting-plug adapted to be inserted therein, and a normally open short circuit about the subsidiary signal and the auxiliary magnet-helix terminating in registering contacts in the spring-jack and connecting-plug. 4:. The combination with a plug-circuit adapted to be temporarily connected with the telephone-line, of a relay having a line-magnet connected with the plug-circuit, a local circuit including a subsidiary signal con trolled by the relay, an auxiliary 1nagnethelix on the relay included in the local circuit, and a plug-seat switch for one of the connecting-plugs adapted to open the local circuit While the plug is in its seat, substantially as described.

In Witness whereof I hereunto subscribe in y name this 3d day of April, A. D. 1895.

CHARLES E. SORIBNER.

Witnesses:

ELLA EDLER, DUNCAN E. WILLETT. 

